CreveTec is offering technology, knowhow and products to improve farming methods of shrimp. The focus is on the nutrition and environment of the shrimp. Shrimp have the potential to grow much faster when they are cultured in ideal conditions. CreveTec is a research based company, specialized in formulation and production of feeds for shrimp and new species. CreveTec offers consulting for aquafeed production and can supply feeds, premixes and dedicated ingredients in cooperation with selected partners. CreveTec also offers consulting for intensive production of shrimp using bioflocs. Services can vary from feasibility study to engineering and turnkey supply.
Production of shrimp started a while ago in a very extensive way. Wild postlarvae were stocked in ponds and natural production in the ponds provided for the nutrition of the shrimp. To increase the production per ha, stocking density was increasing and artificial feeds were developed to complement the natural production. As technology and feeds improved, production per ha increased, but also the limits to the system became clear.
Shrimp differ in a lot to other farmed species:
- Shrimp are benthic. They only use the bottom of a pond.
- Shrimp must find the feed by chemical attraction (olfactory sensors). Feeds should leach substances (often useful nutrients) to attract shrimp to the feed.
- Typically, shrimp feed pellets will stay in the water for 15 - 60 minutes before the shrimp consumes them. But they can lie in water for several hours before consumption and should remain water-stable during this time. During this time, feed pellets swell by taking up water and water-soluble nutrients leach out of the pellets. These nutrients are a loss. In semi-intensive farming, shrimp are typically fed 3-4 times/day. This worsens the problem enormously.
- Shrimp are external masticators, meaning that they chew their feed outside their mouth. They are selective feeders, nibbling on pellets and only consume more feed when palatability is OK: When shrimp start consuming feed, they will not ingest the feed at once. They will nibble on it, select the palatable pieces and throw away whatever they don’t like. The uneaten parts are left and will be digested on the pond bottom by bacteria.
- Shrimps are poor digesters. Their digesting system is rudimentary. A lot of nutrients pass their system without being assimilated. For example, the protein efficiency of shrimp is only 15-20 %.
- In nature, shrimps will consume a lot of pre-digested feed, like rotten fish and detritus. Whatever is not assimilated goes back to nature and is recycled. In ponds however, as density of production increased, these excess nutrients became pollutants, using oxygen and degrading into ammonia, hydrogen sulphide and methane, all toxic to shrimp. To get rid of those pollutants, water is exchanged and the pollutants are flushed out of the system. This way, the chance of recirculating them is lost and the feed will never be utilised at this maximum. This is the main reason why feed conversions in shrimp culture are horribly high and don’t show any progress during the last couple of years.
- Shrimps can consume detritus actively or passively. Soluble nutrients will dissolve in the pond water and feed the natural bloom of the pond: phytoplankton, which in turn will feed zooplankton. The shrimp will ingest some of this plankton again. This is what we call natural production of the pond.
- Crustaceans have some unique nutritional requirements such as phospholipids, cholesterol, Phosphate to Calcium ratio. Knowledge of shrimp nutrition has increased during the years, but application in business has been difficult. Semi-intensive farming is not the system that will maximise shrimp efficiency and different shrimp feed qualities have not show substantial differences in the production. Hence, shrimp producers tend to choose the cheapest feed.
Feeding an animal means giving the animal the nutrients it needs. The first aim should be that the nutrients are actually ingested by the shrimp. As a result a lot of effort has been made to make water stable pellets, which can stay “intact” in water for several hours without falling apart.
However, it is not because the pellets seem to be intact that they actually are. Pellets absorb water (plus the salt minerals with it) and water-soluble nutrients (vitamins, amino acids and peptides, ions) will leach out.
To maximise nutrient re-utilisation, we have to reduce water exchange. This can be done is different ways:
One main factor is aeration instead of water exchange. The nutrient recycling can be done in the same tank of in another tank or pond. What could be called biological treatment of the pollutants would be similar to what would happen in nature, meaning bacterial flocks and substrates for nitrification.
Shrimps can passively ingest and digest some of those bacteria and would graze on the substrates to supplement feeds.
Nutrient recycling is then a reality.
- The aim is to produce shrimp and other crustaceans in the most ecological way.
- This means with optimal utilisation of various resources: water, feed, raw materials, land surface.
All losses (leaching, undigestible food, unnecessary transport of feed, nutrient rich effluents) should be minimized and treated in the following order:
Reduce, Reuse, Recycle
- Reduction of losses: short time between production of feeds and utilisation
- Optimal utilisation: maximum digestibility, good feed quality, feed management
- Treatment and recyling: nutrient recycling through in-pond biological treatment, uptake of nutrients by algae and bacteria
- Effluent treatment: recuperation of nutrients by seaweeds, molluscs, omnivorous fish
- Utilisation of sludges for the production of sea vegetables.
CreveTec will develop technology, alone or with partners, to optimize resources utilisation, step by step.
Crevetec wants to provide a total solution for ecological (and economic) production of shrimp.
This means shrimp will be produced with maximum efficiency of feed and minimum impact on the environment (no effluents). CreveTec can assist you with:
- Consulting for shrimp farming with zero exchange of water, by means of in-pond purification of pond water. Bacterial flocks will return in the pond and recycled by shrimp directly or indirectly. This system can be used for ultra-intensive farming (up to 10 kg/m²) and in existing semi-intensive systems.
- On farm production of tailor-made, high quality feeds. Local (moist) ingredients will be used in the formula together with the necessary imported raw materials and concentrates. Different production systems can be used according to specific conditions on the farm. For small scale production, a cold extrusion system is developped. Focus on those feeds is not low cost, but maximum digestibility/production, and lowest feed conversion.
- Optimisation of feed utilization by close collaboration with the shrimp farmer for feed formulation, logistics, storage and feeding management. We can work with an open formula, which means the farmer can choose with us which quality he wants for his farm and will know how the price of the feed is formed.
- Assistance for existing Aquaculture feed production units: Audit of formulas, raw material sourcing, ingredients to use, production system and quality control.
- Analysis and evaluation of existing shrimp feed brands: leaching of substances.
- Supply of new, innovating raw materials.
- Integrated farming with effluent treatment by ways of growing secundary crops like tilapia, seaweeds of halophytes.
- Contract Research
Development of Ingredients for Aquaculture feeds
- Evaluation of brewery by-products as feeds for the African catfish, Clarias gariepinus and Tilapia.
- Research on the economic feasibility of the utilization of brewery activated sludge in cattle and fish feeds by extrusion and drying.
- Introduction of local ingredients (Tuna fish meal, coral, poonac, hatchery and slaughterhouse wastes) in livestock and shrimp feeds in Seychelles.
- Development and processing of fishery by-product for aquaculture feeds (Bone removal, low temperature drying).
- Processing of vegetable proteins (rapeseed meal) for shrimp feeds (research grant)
- Utilization of animal by-products (blood meal, feather meal, poultry by-product meal, animal protein hydrolysates) in aquafeeds
- Replacement of fishoil by poultry oil in feeds for rainbow trout
Feasibility studies have been carried out for
- Production unit for snacks and breakfast cereals in Seychelles.
- Fish meal and rendering plant in Seychelles.
- Pet food and fish feed production unit in Kuwait.
- Fish and shrimp feed production unit in Suriname.
- Integrated shrimp farm (including feedmill) in Madagascar.
- Production of land crabs in the Caribbean.
- Fish and shrimp feed production unit in Belize.
- Shrimp feed production unit in Peru.
- Integrated, zero-exchange intensive farming of P.monodon in West Africa.
- Integrated production of Macrobrachium in Congo (feedmill, hatchery, farm, processing).
- Zero-exchange indoor shrimp farms in Bulgaria, Belgium, Greece, Canary islands
Development of the production of feeds for shrimp in various countries
- Production of shrimp feed in a livestock feed line. Improvement of the formulation.
- Optimisation of shrimp feed, formulation and production in Seychelles. With this feed the production in an intensive farm increased from a maximum of 3 tons shrimp per pond (0.5 ha) to an average of 5 tons shrimp biomass per pond (average size: 35 g).
- Development of the production of shrimp feeds in India: upgrading of existing shrimp feedmill, formulation of shrimp feeds with local ingredients
- Development of the production of shrimp feeds in Iran: Assistance in design of a new shrimp feedmill with capacity of 3 tons per hour. Formulation of a special high salinity diet for P. indicus which resulted in an improvement of farming results (Shrimp reaching 18-22 g in about 4 months, FCR: 1.1-1.4)
- Development of the production of shrimp feeds in Portugal in an existing extrusion plant for fish feeds: formulation of shrimp postlarval and growout feeds. This feed was exported to various countries in Europe and West Africa.
- Development of the production of shrimp feeds in Madagascar: adaptation of existing livestock feedmill to produce shrimp feeds: design of new machinery to add, start-up of production of shrimp feeds, research in the utilisation of more local ingredients, training of production managers, sales of those shrimp feeds, visiting customers (shrimp farmers).
- Production of feeds for biofloc culture of Litopenaeus vannamei in Belgium, used by 4 farms and 2 research institutes.
- Consulting for a shrimp feedmill in New Caledonia
- Assistance for formualtion and production to various aquafeed producers in India
Feed development and formulation
- Optimisation of a catfish feed
- Least cost formulation of livestock and aquaculture diets
- Formulation of concentrates for various shrimp feed production units.
- Formulation and development of shrimp feeds to various customers in Eastern Africa and the Middle East.
- Research into the leaching of various substances from shrimp feed pellets.
- Development of a low salinity diet.
- Development of a postlarval feed for shrimp in China.
- Evaluation of different binders (wheat gluten, Ureumformaldehyde and gelatin) in shrimp feeds.
- Influence of replacement of wheat flour by Cassava (Tapioca) on pellet quality (water stability, leaching, hardness) of shrimp feeds.
- Development of a shrimp feed without marine proteins
- Day to day running of a feedmill (5 ton/h) which supplies all the animal feed requirements of Seychelles (feeds for layers, broilers, turkeys, ducks, pigs, cattle, horses, rabbits, dogs and cats).
Assistance in design, engineering and upgrading of various feedmills
- Supervision of the construction and starting up of a silo storage and automatic dosing system for raw materials (capacity 1500 MT) in Seychelles.
- Supervising of the construction and start-up of a shrimp feed mill with a capacity of 6000 MT/year (2MT/h)
- Upgrading of the existing shrimp feed mill in Seychelles
- Advise for the design of a shrimp feed mill in Suriname
- Formulation of diets for seabream, seabass and rainbow trout (Turkey)
- Optimisation of a recirculation pilot-scale plant for the culture of eels, catfish and tilapia. Water treatment (sedimentation, aerobic treatment, denitrification)
- Assistance in the development of a broodstock domestication program for P. monodon, with particular attention to the feed during ongrowing of the breeders.
- Assistance in feed management to various customers
- Intensive farming of the north sea shrimp Crangon crangon (research grant)
- Intensive farming of Litopenaues vannamei in an new improved zero-exchange system (research grant)
- Consulting for 2 intensive shrimp farms (P. vannamei) in the Netherlands
- Consulting for an intensive shrimp farm in the US
- Consulting for a trial production of Penaeus monodon in a biofloc system with zero-exchange.